Today, dentists tend to use rotary systems. Despite the increasing diversity of these systems as well as a few studies on the prevalence of pain after root canal treatment by rotary systems, And in particular, comparing the amount of pain after treatment, between systems RECIPROCAL AND FULL ROTATION single-file, the aim of this study was to evaluate the effect of applying canal preparation by the system, Neolix and WaveOne, on the prevalence of pain after endodontic treatments.